ACT Math : How to find the area of a trapezoid

Study concepts, example questions & explanations for ACT Math

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Example Questions

Example Question #1 : Trapezoids

What is the area of this regular trapezoid?

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Possible Answers:

45

20

26

32

Correct answer:

32

Explanation:

To solve this question, you must divide the trapezoid into a rectangle and two right triangles. Using the Pythagorean Theorem, you would calculate the height of the triangle which is 4. The dimensions of the rectangle are 5 and 4, hence the area will be 20. The base of the triangle is 3 and the height of the triangle is 4. The area of one triangle is 6. Hence the total area will be 20+6+6=32. If you forget to split the shape into a rectangle and TWO triangles, or if you add the dimensions of the trapezoid, you could arrive at 26 as your answer.

 

Example Question #2 : Trapezoids

Trap

What is the area of the trapezoid above if a = 2, b = 6, and h = 4?

Possible Answers:

16

24

32

64

8

Correct answer:

16

Explanation:

Area of a Trapezoid = ½(a+b)*h

= ½ (2+6) * 4

= ½ (8) * 4

= 4 * 4 = 16

Example Question #12 : Trapezoids

Find the area of a trapezoid if the height is , and the small and large bases are  and , respectively.

Possible Answers:

Correct answer:

Explanation:

Write the formula to find the area of a trapezoid.

Substitute the givens and evaluate the area.

Example Question #1 : How To Find The Area Of A Trapezoid

Trapezoid  has an area of . If height  and , what is the measure of ?

Possible Answers:

Correct answer:

Explanation:

The formula for the area of a trapezoid is:

 

We have here the height and one of the bases, plus the area, and we are being asked to find the length of base . Plug in known values and solve.

Thus, 

Example Question #1 : How To Find The Area Of A Trapezoid

Find the area of a trapezoid given bases of length 6 and 7 and height of 2.

Possible Answers:

Correct answer:

Explanation:

To solve, simply use the formula for the area of a trapezoid.

Substitute 

into the area formula.

Thus,

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